A review was made of the morphologic alterations induced in human and animal hearts by the administration of anthracycline drugs (doxorubicin and daunorubicin). These agents are currently used for chemotherapy of various forms of cancer, and their use is associated with a significant incidence of dilated cardiomyopathy. Microscopically, this cardiomyopathy is characterized by myofibrillar loss and cytoplasmic vacuolization caused by dilatation of sarcoplasmic reticulum.